铝钢双金属构件触变软芯复合锻造成形技术及协调变形机制研究

In this project, a thixotropic core based compound forging technology is proposed in order to conquer the bottleneck problems of conventionally compound forged aluminum-steel parts, e.g. uncoordinated deformation and pour bonding performance. Thixoformation of aluminum alloy and plastic deformation of steel are integrated effectively to produce aluminum-steel bimetal parts with near-net shape and high mechanical performance. The scientific problems of thixotropic core based compound forging will be studied, e.g. the relationship between internal supporting force and coupling factors of loading rate and microstructures of billets, coordinated deforming mechanism of Al-Steel bimetal, the formation mechanism of metallurgical interface under the coupling factors of partial liquid phase and deformation, and the relationship between compound forging process, microstructures and mechanical properties. A correspondence model based on compound forging parameters, microstructures and mechanical properties of the bimetal components will be constructed, and precision forming of Al-Steel bimetal parts and controlling of mechanical properties can be achieved. This study can combine the advantages of steel (high mechanical properties) and aluminum alloys (light weight), and provide a new method for manufacturing Al-Steel bimetal parts with near-net shape and high mechanical performance, which has important theoretical value and practical application significance.

针对铝钢复合锻造技术存在双金属变形不协调和界面结合性差的问题，本项目提出触变软芯复合锻造成形技术，将铝合金触变成形和钢热塑性成形有机结合，实现高品质铝钢双金属构件形性一体化成形。通过研究触变软芯复合锻造成形中的科学问题，如内支撑力对加载速率-坯料组织状态耦合因素的依赖关系，触变铝芯复合锻造成形过程中的双金属协调变形机制，部分液相和界面结构变形耦合作用下的冶金界面形成机理，复合锻造工艺与构件组织性能的映射关系等，建立整体锻造工艺-复合构件微观组织-力学性能对应关系，实现铝钢双金属构件形性协同控制。本项目研究将钢的高性能优势和铝合金的轻量化优势有效集成，为高品质铝钢双金属构件形性一体化制造提供一种新的方法和思路，具有重要的理论价值和实际应用意义。

本研究瞄准尖端航天器轻量化双金属齿轮精密成形制造需求，针对铝钢变形不协调、界面结合性差、难以实现结构-界面-性能一体化制造的技术瓶颈，提出了铝钢双金属构件触变软芯复合锻造成形新方法，利用触变铝芯流动性好、体积不可压缩等特点，实现铝钢协调变形和可靠界面冶金结合，在可控制备冶金结合界面、实现有效机械互锁、三向压应力抑制偏析方面优势明显。本研究重点围绕铝钢双金属构件触变软芯复合锻造成形界面冶金结合形成机理、铝钢协调变形行为及构件成形机制、组织性能及冶金界面均匀性控制等方面开展了深入研究，解决了铝钢双金属构件复合成形中材料变形不协调、界面结合性差等瓶颈问题，突破了铝钢双金属复合成形构件精密制造瓶颈，可为新一代空天装备轻量化发展提供理论与技术支撑。